Stepped connector body



United States Patent O 3,402,949 STEPPED CNNECTOR BODY John R. Mahoney,Norwood, NJ., assignor to Hoke Manufacturing Company, Inc., Cresskill,NJ., a corporation of New Jersey Filed June 6, 1966, Ser. No. 555,376Claims. (Cl. 285-341) ABSTRACT 0F THE DISCLOSURE An improvement in tubecouplings for the purpose of facilitating reuse of the coupled tube insubsequent connections using a similar connector. The coupling is of thetype wherein a tube is received into a body portion and is attachedthereto with the addition of one or more ring-like ferrules which arewedged between the tube and the body by a coupling nut. The improvementis in the shape of the tube receiving bore in the body. This bore ismade having two adjacent sections of differing diameters connectedtogether by a slanted or flared step. This shaping of the bore causesthe tube when initially attached to the body to have a bulged andconsequently inwardly ared end whose reduced end diameter will easily tinto other bodies regardless of small dimensional variations in the bodysize.

The present invention relates to compression pipe couplings and moreparticularly to an improved body member or tube receiving seat for usein such a coupling.

Compression tube couplings are used to attach tubes or pipes to a bodymember without the formation of threads in the coupled tube itself. Thebody member, for example, may be a tube receiving seat in a valve or agauge or a pipe element such as a T or other pipe element. Couplings ofthis sort, as for example the coupling illustrated in Patent No.3,215,457 owned by the assignee of the present invention, provide for afluid tight connection between a tube and a body using one or morering-like ferrules which draw the tube against the seat and seal itagainst the body under the control of a theraded coupling nut. Suchcouplings are particularly advantageous for thin walled drawn tubingsuch as brass or copper or stainless steel tubing as they permiteffective and extremely strong or fluid tight couplings to be maderapidly between such tubes and various body members by the simpleapplication of the ferrules and the nut and thus without requiring theformation of threads and the use of thread sealing compounds in formingthe connection.

With tubes of this type, however, a problem is presented by the widerange of pipe or tube diameter tolerances encountered. These relativelywide variations in tube size tolerance taken lwith the expected andpermissible tolerance ranges in the receiving bores in the body membersto which the tubes are coupled present problems both in the initialsealing and 4more signicantly in the resealing or replacement operationswhere it is desired in a completed system to replace one coupled elementor body member with another. Specifically trouble is encountered when atube which has been previously applied by a compression coupling isdeformed to the extent that it will not thereafter t into or seal asubsequent body member.

The present invention provides a novel -body shape and a relatedcoupling method which assures that tubes within the entire expectedtolerance range will be initially connected and sealed to a first bodyhaving any receiving bore within the normal bore tolerance range andwill thereafter be again sealed and coupled to a second member having adiffering bore within the bore tolerance range. This improved result isobtained by a novel step element provided in the seating bore preferablyin combination with a flared tube seat shoulder as will be more fullydescribed below.

ice

Accordingly, an object of the present invention is to provide animproved compression-type tube coupling.

Another object of the present invention is to provide an improvedcompression-type tube coupling useful for successively coupling bodieshaving differing seat bore diameters.

Another object of the present invention is to provide an improved bodyshape for the body portion of an element in a threadless compressiontube coupling.

Another object of the present invention is to provide an improved meansand method for coupling and recoupling a tube using a threadlesscompression coupling.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodiment about to be described orwill be indicated in the appended claims, and various advantages notreferred to herein will occur to one skilled in the art upon employmentof the invention in practice.

A preferred embodiment of the invention has been chosen for purposes ofillustration and description and is shown in the accompanying drawings,forming a part of the specification, wherein:

FIG. 1 is a vertical sectional View of a completed coupling having astepped body in accordance with the present invention; and

FIGS. 2-4A are enlarged detailed sectional views illustrating thecoupling action of a stepped 4body in accordance with the presentinvention for tubes and bodies having differing relative diameters.

The improved body 1 in accordance with the present invention will bedescribed as used with a compression-type coupling having twocooperating ring-like ferrules 2 and 3 which simultaneously physicallycouple the tube to the body While forming a fluid tight seal with thebody. Such a coupling, for example, is illustrated in the above notedpatent.

This threadless coupling has the ring-like ferrules 2 and 3 asillustrated in FIG. 1 whose inner surfaces and front edges 4 and 5 inparticular are forced inwardly against the tube 7 under the force of thethreaded coupling nut 6 as the nut 6 is turned onto suitable threads 8on the body 1. For convenience, a threaded nipple is illustrated as the4body portion in the following description, however, it is to beunderstood that the nipple is merely illustrative and a tube receivingbore in accordance with the invention may be provided on Variouselements such as valves and gauges, etc.

The tube receiving bore 9 in the body 1 includes an outer flared portion10 terminating in a cylindrical inner bore 1-1 whose detailed shape inaccordance with the present invention will be described further below.The above described ferrules include the inner ferrule 2 with a flaredouter surface 12 which engages with the flared surface 10 of the bore 9to force the inner edge 4 of this ferrule inwardly as the nut 6 isapplied resulting in a corresponding inward movement in the tube 7tightly against the bore shoulder ,14 and :a subsequent furthercontrolled penetration of the ferrule edge 4 into the tube 7 to providea combined mechanical and fluid seal between the tube 7 and the body 1.The second or rear ferrule 3 illustrated in FIG. 1 has a concave outersurface 15 engaging a complimentary concave surface 16 at the rear ofthe front ferrule 2 which provides for a further sealing action of thecombination as the rear ferrule 3 rolls or gyrates inwardly against thetube 7 in the general manner illustrated in FIG. 1.

The :above described ferrules and nut are typical of those useful withthe improved body of the present invention, however, it lis clear thatother types of ferrules which act to force the tube 7 inwardly and whichprovide a mechanical and uid seal are equally useful with an improvedtube receiving body in accordance with the ever, the relatively shortstep 20c engages a minimal present invention. annular area along thetube 7c as the tube end 21C is The various tubes attached to thefittings by such comforced inwardly and formed with a constricted tubeend pression couplings are most often formed by :an extrusion and as thetube end 21C moves into abutting engagement process but regardless oftheir manner of formation these with the flared tube seat shoulder 14C.Even with this tubes have a relatively -wide diameter tolerance range.relative diameter relation, it is clear that the step 20c The largertubes may just barely fit into the internal bore functions to prov-idefor a full seating of the tube 7c of the corresponding tting tube seatparticularly where and a simultaneous constricting of the tube end tothe fitting itself has an inner diameter at the minimum facilitatereassembly of the same tube with another body end of the bore tolerancerange. Where such a fitting and 10 or fitting having a similar ordiffering seat diameter withtube are matched in the initial couplingeven the slightest in the expected seat diameter tolerance range.out-ward flare of the tube end resulting from the applica- The abovedescription of the step space-d outwardly tion of the ferrules and thenut may prevent the subof the shoulder and operating as indicated toconstrict sequent reassembly of the tube as the flared tube may the tubeend clearly indicates the method and means for have an outer diameterlarger than that of the subsequent obtaining an improved coupling. Thespacing of the step tube receiving bore in the body to which it may benecesoutwardly of the shoulder as indicated by the dimension sary thatit be attached. C in FIG. 2 provides a significant feature of theimprove- A novel step design of the present invention prevents ment. Asthe dimension C is reduced to zero the advantage this subsequent misfitof the tube and body by forming of an early engagement between the tubeend and the an inward taper on the tube end during the initial coustepis lost with a corresponding loss of assurance that pling. The formationand action of the step will now be the tapering action has actually beenperformed and in described in greater detail with particular referenceto addition the tapering is limited to an unsatisfactorily short theenlarged and detailed FIGS. 2 thru 4A which show portion of the tube endresulting in both a constriction the operation of the step for variousrelative diameters inadequate in amount and formed with greaterdifficulty. of the tube 7 and body I. FIGS. 2 and 2A illustrate the 25Representative angles A and B for the shoulder and step conditions whichexists for a relative small tube and a as indicated in FIG. 2 as well asthe diameters of the large seat. This condition may result for tubeshaving sections of the tube bore in the stepped body for severaldiameters at the small end of the tolerance range or fitting sizes areindicated below. These dimensions and for average tubes being fittedinto a body having a bore angles are not considered to be limiting andare quoted -of maximum diameter. FIG. 2 shows the tube 7a being 30 forillustrative purposes only as it is believed that the inserted into thebody la with the tube inner end adabove general discussion gives aycomplete and clear dejacent to but passing under the step 20u. FIG. 2Aillusscription of the improved stepped body design.

REPRESENTATIVE DIMENSIONS Fitting Shoulder Step Length Fitting Step BoreNominal Size Angle Angle C, -l-.05 Diameter Diameter Diameter Tue tratesthe tube 7a fully seated with the tube end engaging It will be seen thata substantial improvement has the ared seat shoulder 14. The are of theshoulder been provided for compression-type couplings which ex- 14forces or holds theend of the tube 7a outwardly aS tends the usefulnessof these couplings and permits ready the tube a150 bulges 'foward thebof@ 9- The Step 20a assembly and reassembly of fluid systems employingsuch limits the outward flare of the tube end on the shoulder couplings.The improved results are obtained by a signifi- 14 and also prevents thetube bulging from occurring at cant but relatively easily made change inthe shape of the the end. The tube 7a -will now enter a subsequent bodytube receiving seat or bore. This change may be usefully even though thebody may have a tube receiving bore employed with a variety of couplingswhere tubes are diameter at the smaller end of the tolerance range. AS rforced into bores during the formation of the couplings in FIG. 2A,there is sufficient clearance between the tube "0 using suitableferrules or other coupling members. end 21a :and the inner surface ofthe bore 22a to permit As various changes may be made in the form,construcreassembly even for smaller body bores. tion, and arrangement ofthe parts herein without depart- FIG. 3 illustrates an intermediaterelationship which ing from the spirit and scope of the invention andwithmay be encountered with a median tolerance for both the routsacrificing any of its advantages, it is to be understood tube 7b andbody 1b or where both the tube and the "D that all matter herein is tobe interpreted as illustrative body are both large or are both small. Inthis condition and not in a limiting sense. the end 2lb of the tubeengages the inclined step 20b. Having thus described my invention, Iclaim: As the end 2lb passes along the step 20b it is necessarily 1 In acompression tube coupling having a body with forced inwardly as the tube7b moves to the final posia tube receiving bore and with the bore havinga flared tion as illustrated in FIG. 2A. It will be seen that a 60 outerend portion and the coupling including a tapered relatively shortsurface only of the step 20h engages the ferrule and a ferrule engagingnut for moving the tube tube surface so that a tapering action isprovided without into the bore and forcing the end of the tube in placea substantial resistance being generated against the full against ashoulder portion at the inner end of said bore seating action of thetube 7b as the ferrules and nut move with the ferrule wedged betweensaid iiared portion and the tube to its final position. This facilitatesthe applithe tube the improvement which comprises said body cation ofthe coupling and also insures that the tube 7b bore having a cylindricalenlarged diameter portion inwill move completely into its finally seatedposition, as wardly of the flared end and being engaged with anoutilustrated in FIG. 3A, to assure :a tight coupling while at wardlybulged portion of the tube7 said enlarged diameter the same timeachieving the desired taper to facilitate rebore portion being connectedwith a cylindrical lesser assembly in the manner described above.diameter bore portion by a flared annular step, the inner FIG. 4illustrates another relative position which may end of said lesserdiameter portion terminating in said be encountered in coupling a tubeto a body having a bore shoulder portion, and said tube having aninwardly minimum bore. In this case, :as seen in FIGS. 4 and 4A flaredportion spaced from the tube end and engaging the tube 7c moves -intosliding engagement with almost said flared step.

the entire surface ofthe step 20c. Even in this case, how- 2. Thecoupling as claimed in claim l in which the shoulder forms an acuteangle with said lesser diameter cylindrical portion of the tubereceiving bore.

3. The coupling as claimed in claim 1 in which said shoulder forms anangle of about 72 to 78 with said lesser diameter cylindrical portion ofthe tube receiving bore.

4. The coupling as claimed in claim 1 in which said step portion isstraight in cross-section and forms about a 15 to 17 angle with saidcylindrical portions.

S. The tube coupling as claimed in claim 1 in which the enlargeddiameter portion of the bore has a diameter larger than the greatestnominal tube diameter for that coupling, and the lesser diameter portionof the bore has a diameter larger than the smallest nominal tubediameter and smaller than the greatest nominal tube diameter.

References Cited UNITED STATES PATENTS 3,069,188 12/1962 Crawford285-342 CARL W. TOMLIN, Prima/'y Examiner.

1 W. L. sHEDD, Assistant Examiner.

